What formula is used to determine safe towing speed?

The formula for determining safe towing speed is based on the principle of ensuring the towing vessel operates efficiently while maintaining safety for both the towing vessel and the tow. The correct approach utilizes the mathematical relationship expressed as 1.34 times the square root of the length at the waterline. This formula is derived from the need to account for the vessel's hull form, water conditions, and stability at various speeds.

Using the square root of the length at the waterline helps to establish a safe operating speed that minimizes the risk of capsizing or excessive heaving in waves, which can occur at higher speeds. By including a negative adjustment, as suggested in the choice, the resulting speed is conservative, ensuring added safety margins in often unpredictable marine environments. This approach recognizes that certain operational risks can arise when towing, particularly with varying tow weights or sea conditions.

The other choices adjust the formula upwards or provide alternative calculations that could lead to an unsafe speed for towing situations, which do not align with maritime safety principles that prioritize lower speeds to enhance control and stability during towing operations.